We have evaluated some azo pigment carrier generation materials in a layered organic
photoreceptor in terms of electrophotographic sensitivity and color reproduction, and
found a dihydro-thiadiazepine derivative azo pigment which shows high sensitivity and
excellent color response. Fixing carrier generation material(CGM) at this dihydrothiadiazepine
derivative and selecting some conventional carrier transport materials(CTM),
we have investigated effects of carrier mobility in a carrier transport layer(CTL),
carrier injection efficiency and carrier generation in CGL on the electrophotographic
sensitivity. If we assume carrier generation in carrier genaration layer(CGL) is well
represented by carrier peak current, the electrophotographic sensitivity has been found to
show the closest corelation with the carrier peak current. The carrier peak current also
shows close corelation with carrier life time in CGL which is strongly influenced by CTM.
We propose a mechanism that explains how CTM affects electrophotographic sensitivity of
layered organic photoreceptor.